class_docstr: Simple scheduler that just runs trials in submission order.
code: def choose_trial_to_run(
      self, tune_controller: "TuneController"
  ) -> Optional[Trial]:
      for trial in tune_controller.get_trials():
          if trial.status == Trial.PENDING:
              return trial
      for trial in tune_controller.get_trials():
          if trial.status == Trial.PAUSED:
              return trial
      return None
  
imports: from typing import Dict, Optional, TYPE_CHECKING
  from ray.air._internal.usage import tag_scheduler
  from ray.tune.result import DEFAULT_METRIC
  from ray.tune.experiment import Trial
  from ray.util.annotations import DeveloperAPI, PublicAPI
label_desc: Use image node_id 7 for calling the FIFOScheduler obj's underlying member method code with example usage: obj.choose_trial_to_run(tune_controller) and returns: None, trial, trial